When a long-term effect of a therapeutic drug for the intrauterine, intravaginal or intrapelvic administration or for the administration into the ovarian endometrioma is required, the drug has to be employed as a pharmaceutical preparation wherein the drug is supported by a carrier.
For instance, a drug for the treatment of endometriosis, such as danazol or Gm-RH analogues, has been orally or subcutaneously administered. In these cases, however, patients have frequently been subjected adverse effects such as liver functional impairment, weight gain, sterility, menstrual disorder, dropsy, hot flush, shoulder stiffness, headache and osteoporosis. The Japanese Patent No. 2590358 discloses a preparation for the intrauterine device, in which danazol as a drug for the treatment of endometriosis is supported by silicone as a carrier in order to avoid those adverse effects.
Regarding the aforementioned preparation, however, a releasing efficiency of the drug from silicone is insufficient. Further, there is concern with the adverse effect of the silicone carrier for the uterus. Since the silicon carrier remains in the uterus after the completion of the release of the drug, it is necessary to remove the silicone carrier from the uterus and thus patients are subjected to the physical or mental burden.